Field of the Invention
The present invention relates to a sputtering target for forming protective film which is used when forming protective film that protect a Cu wiring film including copper or a copper alloy, and a laminated wiring film including a protective film formed by using the sputtering target for forming protective film.
The present application claims the right of priority to Japanese Patent Application No. 2013-027046 filed on Feb. 14, 2013 in Japan, and the contents thereof are incorporated herein by reference.
Description of Related Art
In the past, Al was widely used in wiring film for flat panel displays such as liquid crystal or organic EL, panels or touch panels. In recent years, an attempt has been made to reduce the size (width) and thickness of wiring film, and there has been a demand for wiring film with a lower resistivity than those in the past.
As the size and thickness of wiring film are reduced, wiring film for which copper or a copper alloy that is a material with a lower resistivity than Al is used are provided.
However, there was a problem in that Cu wiring film including copper or a copper alloy with a low resistivity were easily discolored in a humid atmosphere. In a case in which a copper alloy containing a large amount of additional elements to improve weather resistance is used, the resistivity increases.
Therefore, for example, Japanese Unexamined Patent Application, First Publication No. 2012-193444 proposes a laminated film having a protective film including a Ni—Cu—(Cr, Ti) alloy formed on a Cu wiring film and a sputtering target for forming the protective film. Since the protective film has superior weather resistance to copper, it becomes possible to suppress discoloration of the surface even when the laminated film is stored in the atmosphere.